NOAA Technical Memorandum NMFS-AFSC-49 Data Report: 1990 Gulf of Alaska Bottom Trawl Survey by J. W. Stark and D. M. Clausen U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Marine Fisheries Service Alaska Fisheries Science Center January 1995 NOAA Technical Memorandum NMFS The National Marine Fisheries Service's Alaska Fisheries Science Center uses the NOAA Technical Memorandum series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible. Documents within this series reflect sound professional work and may be referenced in the formal scientific and technical literature. The NMFS-AFSC Technical Memorandum series of the Alaska Fisheries Science Center continues the NMFS-F/NWC series established in 1970 by the Northwest Fisheries Center. The NMFS-NWFSC series will be used by the Northwest Fisheries Science Center. This document should be cited as follows: Stark, J. W., and D. M. Clausen. 1995. Data Report: 1990 Gulf of Alaska bottom trawl survey. U.S. Dep. Commer., NOAA Technical Memorandum NMFS-AFSC-49, 221 p. Reference in this document to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA. NOAA Technical Memorandum NMFS-AFSC-49 Data Report: 1990 Gulf of Alaska Bottom Trawl Survey by J. W. Stark 1and D. M. Clausen2 1Resource Assessment and Conservation Engineering Division Alaska Fisheries Science Center 7600 Sand Point Way N.E., BIN C-15700 Seattle, WA 98115-0070 2Auke Bay Laboratory Alaska Fisheries Science Center 11305 Glacier Highway Juneau AK 99801-8626 U.S. DEPARTMENT OF COMMERCE Ronald H. Brown, Secretary National Oceanic and Atmospheric Administration D. James Baker, Under Secretary and Administrator National Marine Fisheries Service Rolland A. Schmitten, Assistant Administrator for Fisheries January 1995 This document Is available to the public through: National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield. VA 22161 Notice to Users of this Document This document is being made available in .PDF format for the convenience of users; however, the accuracy and correctness of the document can only be certified as was presented in the original hard copy format. iii ABSTRACT The third triennial groundfish assessment survey of the Gulf of Alaska was conducted during the summer of 1990 by the Alaska Fisheries Science Center's Resource Assessment and Conservation Engineering (RACE) Division and the Auke Bay Laboratory (ABL). Two chartered trawlers, the Pat San Marie and Green Hope and the National Oceanic and Atmospheric Administration research vessel Miller Freeman successfully sampled 708 survey stations in the Gulf of Alaska from the Islands of Four Mountains (1700W long.) to Dixon Entrance (133°25'W long.) in depths less than 500 m using standard RACE Division Nor'eastern high-opening bottom trawl nets with rubber bobbin roller gear. This document combines the results of the RACE and ABL surveys. The survey design divided the overall Gulf of Alaska survey area into 49 strata based on bathymetric and geographic features to produce a standard survey area totaling approximately 87,000 square nautical miles (nmi2) (296,700 km2) ranging in bottom depth from 1 to 500 m. Trawl samples were allocated among strata in proportion to fish densities observed during the 1984 U.S.-Japan triennial survey. Stations were selected randomly from a 5 by 5 nmi grid of numbered points, superimposed over each stratum. The bottom area swept during each trawl haul was determined from an acoustic trawl mensuration system and Loran navigational equipment. The species composition was determined for each catch and the principal species were sampled for sex, length, individual iv weight and age distributions. Seawater temperatures were collected during trawling operations. Ancillary collections included specimens for diet studies, juvenile walleye pollock (Theraqra chalcoqramma) distribution and predator studies, skate taxonomic delineation, fishery observer training and marine mammal prey studies and sightings. Results include a ranking of catch abundance for the 20 most abundant species, abundance estimates of the principal fish species, distribution, and size composition by geographic location and depth and length versus weight regression parameters. Age composition data are included for walleye pollock and Pacific ocean perch (Sebastes alutus). Seawater surface and bottom temperature data are presented by area. Appendices contain the survey trawl specifications and diagram, strata definitions and charts, list of species encountered and length-weight relationships of the principal species. Arrowtooth flounder (Atheresthes stomias), walleye pollock, Pacific halibut (Hippoqlossus stenolepis) and Pacific cod (Gadus macrocephalus) were the dominant species throughout the survey area. The rockfish, sablefish (Anoplopoma fimbria), soles and other species were locally abundant in some areas. Red squid (Berrvteuthis maqister) was the most abundant invertebrate throughout the survey area. v CONTENTS Introduction 1 Methods 3 Vessels and Gear 3 Survey Area 4 Sampling Design 8 Western and Central Gulf of Alaska 8 Eastern Gulf of Alaska 10 Overall Gulf of Alaska 12 Collection and Processing of Samples 13 Data Analysis 16 Results 19 Water Temperature Distribution 26 Overall Abundance and Distribution of Major Fish Groups 32 Principal Fish Species Abundance, Distribution and Size Composi tion 35 Arrowtooth flounder 36 Pacific halibut 42 Flathead sole 48 Rock sole 54 Rex sole 60 Dover sole 66 Yellowfin sole 72 Walleye pollock 78 Pacific cod 84 Sab Iefish 90 Pacific ocean perch 96 Northern rockfish 102 Rougheye rockfish 108 Dusky rockf ish 114 Sharpchin rockfish 120 Shortraker rockfish 126 Shortspine thornyhead 132 Other rockfish 138 Other flatfish 148 Skates 153 Smelt 155 Pacific herring 155 Atka mackerel 155 Red squid 155 Age Composition Data 161 Ci tations 164 Appendix A Gear Specifications and Diagram 165 Appendix B Strata Specifications and Charts 167 Appendix C List of Animal Species Encountered 176 Appendix D Length-Weight Regressions for Major Species 185 Appendix E Catch Per Unit of Effort and Biomass Estimates by Strata for Principal Species 199 vii PREFACE This data report is one of three types of standard reports presenting data from the 1990 Gulf of Alaska groundfish survey conducted by the National Marine Fisheries Service (NMFS). These reports are: 1) A Cruise Report1, outlining the survey objectives, documents itinerary, personnel, vessels employed and summarizes major accomplishments. 2) A Report to Industryl, containing a fishing log consisting of raw haul and catch data for each haul made during the survey, catch summaries for the major species catch per unit effort by haul and gear specifications and diagram. 3) A Data Report (this document), containing detailed descriptions of the survey planning and operation, species distribution and abundance charts, length frequency plots, tables of estimated biomass, catch per unit of effort, average weight and length estimates, length frequency plots, length-weight regression parameters, sea temperature charts, list of species, survey strata specifications and charts, trawl descriptions and diagrams. lCentral and western Gulf of Alaska survey area reports are available from Director, Resource Assessment and Conservation Engineering Division, Alaska Fisheries Science Center, National Marine Fisheries Service, 7600 Sand Point Way N.E., Building 4, BIN C15700, Seattle, WA 98115-0070. Eastern Gulf of Alaska survey area reports are available from Director, Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, 11305 Glacier Highway, Juneau, AK 99801-8626 INTRODUCTION The third in a series of triennial groundfish surveys was conducted in the Gulf of Alaska (GOA) during the summer of 1990 by the National Marine Fisheries Service's (NMFS) Alaska Fisheries Science Center (AFSC). Survey design and operations were the responsibilities of scientists from the AFSC's Seattle based Resource Assessment and Conservation Engineering (RACE) Division for the western and central GOA (Islands of Four Mountains to Cape St. Elias). The eastern GOA (Cape St. Elias to Dixon Entrance) was the responsibility of the AFSC's Auke Bay Labor~tory (ABL) located in Juneau, Alaska. This report presents the combined survey results for the principal fish species in each of the five GOA International North Pacific Fisheries Commission (INPFC) statistical areas: Shumagin, Chirikof, Kodiak, Yakutat, and Southeastern. The purpose of this report is to provide fishery resource managers with results of the two 1990 GOA groundfish surveys, to supplement the status of stocks resource assessment and allocation process. This report presents the 1990 survey results only and makes no comparisons with previous GOA surveys. The survey objectives were to: 1) Delineate the distributions of major groundfish and commercially important invertebrate species inhabiting the Gulf of Alaska between the inner continental shelf and upper continental slope in water depths to 500 m. 2) Collect data to estimate the abundance of the major groundfish species. 2 3) Collect data to define biological parameters for size, sex and age composition, growth, length-weight relationships and reproductive condition. 4) Collect accurate trawl performance data for all survey nets and vessels. 5) Conduct cooperative sampling with other research organizations.